1. Field of the Invention
The present invention relates to a decomposition apparatus and a decomposition method suitable for the decomposition/removal of hazardous materials (contaminants) such as organic chlorinated compounds in a gaseous or mist state, and to a decomposition apparatus and a decomposition method for substances.
2. Related Background Art
Organic chlorinated compounds used to clean machinery are often found to be contaminating the soil of vacant lots where factories or dry cleaning establishments used to stand. Such organic chlorinated compounds are chemically stable, and this has drawn attention to cleaning the contaminated soil in recent years.
Some of the methods for decomposing/removing organic chlorinated compounds include incineration, thermal decomposition, photolysis, oxidative decomposition, reductive decomposition, using catalysts, and microbial decomposition. Besides these, electrolysis has been developed as a decomposition/removal method. The electrolysis method is a technology in which contaminated water containing organic chlorinated compounds is energized to alter electrode surfaces to an oxidative or reductive state, which decomposes the contaminants through oxidation-reduction reaction and makes them harmless.
However, in such a conventional electrolysis method, electrodes cannot be inserted into organic chlorinated compounds in a gaseous or mist state extracted from contaminated soil to be energized. There is a method to absorb organic chlorinated compounds in a gaseous or mist state into a liquid phase and energize the liquid phase to electrolytically process it, but this requires a separate processing for the liquid phase after the organic chlorinated compounds are absorbed.
It is known that as the concentration of contaminants increases, so does the electric decomposition efficiency per unit electrical charge. However, when the liquid phase that has absorbed an organic chlorinated compound is electrolyzed, the concentration falls as the decomposition process continues, so that the decomposition efficiency per unit time declines.